charmcraft won't build 18.04 bionic charm for local-users

[Drew Freiberger]

There's an incompatibility in the build pipeline for bionic when performing a `charmcraft pack` on the main branch.

jinja2 < 3.0 in the requirements.txt pulls in MarkupSafe>=0.23 which results in MarkupSafe==2.0.1 currently. This causes the build to fail with an error that there's no module markupsafe found.

When adding MarkupSafe < 2.0 (resulting in MarkupSafe == 1.1.1) into the requirements.txt, the build error for bionic changes to an issue of the setuptools/setup.py within the venv having an error that it cannot find `find_dependencies:`.

2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.135 :: 2022-03-14 17:00:33.135 :: Complete output from command python setup.py egg_info:
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.135 :: 2022-03-14 17:00:33.135 :: running egg_info
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.135 :: 2022-03-14 17:00:33.135 :: creating pip-egg-info/importlib_resources.egg-info
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.135 :: 2022-03-14 17:00:33.135 :: writing pip-egg-info/importlib_resources.egg-info/PKG-INFO
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.136 :: 2022-03-14 17:00:33.135 :: writing dependency_links to pip-egg-info/importlib_resources.egg-info/dependency_links.txt
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.136 :: 2022-03-14 17:00:33.135 :: writing requirements to pip-egg-info/importlib_resources.egg-info/requires.txt
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.136 :: 2022-03-14 17:00:33.135 :: writing top-level names to pip-egg-info/importlib_resources.egg-info/top_level.txt
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.136 :: 2022-03-14 17:00:33.136 :: writing manifest file 'pip-egg-info/importlib_resources.egg-info/SOURCES.txt'
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.136 :: 2022-03-14 17:00:33.136 :: error: package directory 'find_namespace:' does not exist
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.136 :: 2022-03-14 17:00:33.136 ::
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.173 :: 2022-03-14 17:00:33.136 :: ----------------------------------------
2022-03-14 12:00:33.587 :: 2022-03-14 17:00:33.206 :: 2022-03-14 17:00:33.173 :: Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-auqgui8l/importlib-resources/ Traceback (most recent call last):

[Drew Freiberger (afreiberger)]

Ultimately, there's a charmcraft bug for this which affects all charmhelpers charms.

https://github.com/canonical/charmcraft/issues/632#issuecomment-1019342531

Workaround by adding this to charmcraft.yaml:

parts:
  charm:
    charm-python-packages: [setuptools < 58]